BACKGROUND: Fluorescence optical imaging (FOI) enables visualisation of inflammation in both hands in rheumatoid arthritis (RA). OBJECTIVE: To investigate the usefulness of FOI in treatment monitoring under anti-TNFα therapy with certolizumab pegol (CZP) in patients with RA in comparison to clinical and laboratory outcome parameters. METHODS: CZP-naïve patients with RA were eligible for this open-label study with an observational period of 52 weeks. Disease activity was monitored by the clinical score DAS28, tender/swollen joint count (TJC-28/SJC-28) and laboratory outcomes for systemic inflammation (CRP and ESR). FOI results were analysed in three different phases (P1-3) and PrimaVistaMode (PVM) by the FOI activity score (FOIAS). RESULTS: Twenty-eight RA patients (median age 52.5 years, 26 females, thirteen with a history of other biologic therapy) were included. DAS28 (CRP) decreased from moderate disease activity at baseline (median 4.6, IQR 1.8) to low disease activity at week (w)52 (median 2.7, IQR 2.1; p < 0.001). Statistically significant decreases could also be demonstrated for SJC-28 and TJC-28. CRP/ESR were reduced numerically from baseline to w52. FOIAS in P1 (early phase) showed a continuous decrease of enhancement during the course of treatment period: from baseline (median 1.5, IQR 9.3) over w6 (median 1.0, IQR 3.0; p = 0.069), w12 (median 0.5, IQR 3.0; p = 0.171), w24 (n = 27, median 0.0, IQR 3.0; p = 0.004), until w52 (n = 18, median 0.0, IQR 2.8; p = 0.091), which could not be presented for FOIAS in P2, P3 and PVM. CONCLUSION: FOI in P1 appears to be a valuable tool for fast and easy monitoring of treatment response to certolizumab in a clinical setting.